Hydrostatic weighing scale



March 20, 1951 A, F, JACKSON 2,545,923

HYDROSTATIC WEIGHING SCALE Filed Jan. 17, 1948 2 Sheets-Sheet l I n HLE'XHNDER T. JACKSON, L/ 4BY// March 20, 1951 A, F, JACKSON 2,545,923

HYDROSTATIC WEIGHING SCALE Filed Jan. 17, 1948 2 Sheets-Sheet 2 fai- W j 2 j 'Y fatentec Mar. 20, 1951 5H'YDRE)SIAF-TIC WEIGHI-NGLSCALE 4: Alexander F. Jacks 011;. East Orange,7 N. J.

i Applica-tion January 17;'19'48; Serial No;A 25930 5 Elaims.

This inventions relatesfifgenerally to; `.weighing Scales, andV more.y particularlywto axshydrostatic l Weighing scale -Which1luti1izesf'the'- flavv of; dis- Yplacement of. a" oatingnbodyj?. that :isftl1eirule :'-lthat a body'iioati-ng in.aliquidflosesiin.Weight the-weight of fthefvolume of such;- liquid ,displacement.

:In its broader aspects,y ithe. invention.: contemlplates acylindricalscupshapedplungeroat/haw ing an anvil or pan to receive articlesto yloel-4r A Weighedf-andi novel,- -and improved f-'meansi for Aguidingr said'l-'fioatuin'A ai: true A'verticalrmovement and for ensuring the least possible friction-in the guidingwmeans. TheLaccuracycfs-Weighing with this device depends on the amount fofthe i i immersion w Of- "the il plunger 'intofits Vsupporting "'liduid=ivhicl11is=shown byL-:the liquid suriaceontact Witnthe! plunger. I* The# plunger: isi provided with agraduated scale/Which# preferablyfconsists "'lplungersffweight' (vvithnotl'ling-4 tolfweighfon rits efanvii) vlis 1*slwvvr'r by-the lfzeroofr 'thefgraduat'ed `scale.' Thereforeg-any-thing-'a-dded'tothelplungers weight;- -for example; :by an artielef pla-eed on .said anvil; fvvilllbe accurately-weighed thee-additional Y'immersioniofl thelplunger into the"y liquid indicates V` 1011" the scale.

outer'1ves'selor-container with transparent-1walls, -in= fwhich shall-Joelmounted-novel and `4improved means-for supporting and guidingsaidJpl-unger wioatuv and a novelV supporting .base forssaidffcontainer= whereby? the latterfcan'I-be accurately-lad? ijustedf-to ensure-'true vertiale movement fot Jsaid =`f-plunger-oat.

nimprnvedl i features'vof fconstruction;rwherebya. a`r` 1`1f1inimum' 'fof liquid-.1fsllall A. be wrequir'ed. and the weighingof1anf=article:shallfnot be' dependenton `the exactfv'olumeof :the liquidl .in-lith@ 'container .eas :long Aas-theref is enough.. liquid to permitgthe `iplunger.'with'.its maximumloadztofffioat.

iwAnother 1f objectf-is'z'to provvidefnovek andzgim- -proved 'meansfor f adjusting the .I plunger14 axis "to a' true=verticalpositioni Afu'rtherobj ect is to:provide-:novelfmeans @to lfacilitate" the positioning iof1 articles- ,t'o beaveignede ori-'fthe saley-'particularlyriylindrical@articles:'of different `diametersf such ias'mailingntubes.

l1' 'Still another 'objectis 'tofprovide a;l weighing scale of this typtlrat isfaccurateg simplewinfco-n- 'istructionsfand "inexpensive to' manufacture.

#Figure 4; isl auhorizontal-Jsectionalfiviewitaken --'-onfthe plane offthelzline lL-Mof Figure `3.

J Asjshowninithefxdrawings the'sscale-:comprises l 5tioorsother-r suitable transparent materialseat'ed f1 onfan annular-base v2-of rubber-ot'suitable' density.

The: --base VVis formed'- Witl-imany inwardly extend- 'other supporting Tlangel 4 midway its L--heigliirof 20larger-farea-'than the ange 3 tand slightlyrourv'ed -Y=downwardlymand inwardly 'with a segmental VAspherical vupper face.

The--outerfvessel le isr--formedwithv-an integral bottom Wall 5 having anfenlargedperipheraledge portionC 6 suitably--A-extended-finto: a-per-ipheral --ange 1- ofthe-VesselY l Thebottom surface fof -i "the" enlarged portion` 5-1 is "shaped -to-conform-=to thespfhericalfshape of 'thel'ange' 4foffthe-ba'se uponfvvhieh#v itA rests. A space 8. is'sprovidedubego-tween"1 the outerf'lvessel I andthef/inneri edgefof ftheeange 3 #oflthe-'baseso thattl1 -,\-oi-iterz vessel can be' tilted'- slightly upon; its `seator-i--the-'loasein `any directionv should the surfaceupon whichi the pase rests be slightly :onf-thehorizontaluthefcontactfof the liquid'W-ith thelplungers'circumferen- 1- --tiallycontinuous r`measuring lines (hereinafter @specifically deseribedhindicating -the truevertical fpositioning.

The outer vessel is partly filled -with aifquan- #inside theV outer-vessel or container `vand'iswpa'rtly submergein the liquid.- Aftubular-zmemloerfor stem "H isfmountedcentrally:on the bottomwvall M-fof the plunger with its-lower ared- 'edgel 2 Welded or otherwise :suitably i i fastened@ -to a*Nl central countersu11kportionfof the'hOttOmi-i-Wall. f The tubular-member extends upWa-rdlya'bove theopen `top end- -othelplunger -andf its.v top -end--is..closed by` a-WallvlS which servessas a scalefpanoranvil forsupporting the articleor-artieles to be weighed.

` Wall 3 l is provided3 With-fupwardb-pro-jections#I4 A--unequallyspaced inl-pairs therearound' fonfprop- 4erly -positioning= -the larticle yfor articles? be s-weighed such-as ator tubulararticlesf In-*crossstantly change or shift.

3 section the cylindrical diameter of the plunger is the same throughout its height.

The outer surface of the Wall of the plunger I is provided with a graduated scale consisting of continuous circumferential lines, the Zero or minimum weighing line of which is at the level of the liquid when the device is not in use as shown in Figure l.

When an article to be weighed is placed on the scale pan I3, the plunger I is moved farther downwardly into the liquid, thereby displacing more liquid and thus raising the level of the liquid which in conjunction with the scale on the plunger measures the weight of the article.

In order to center the plunger in the outer vessel or container and to guide its up and down movements, the outer Vessel is provided with a tightly fitting cover member I5 of a suitable material for supporting, centering and guiding devices for the plunger. An opening I6 is formed f in the center of the cover member and depending from the underside of the cover member around said opening is an integrally form-ed tubular stem Il with a plurality of spaced elongated openings IS near the lower end when desired for reducing the Weight of the device.

An upper series of three adjustable metal guiding and centering devices I9 are supported by equally spaced perforated ear or bracket portions 2G` formed integrally on the wall of the tubular stem lI'I between the 'openings I8 adjacent its upper end. A lower series of three similarly constructed and mounted guiding and centering devices 2I is positioned directly below the upper series. Each guiding and centering device comprises a cylindrical body portion 22 and a screw threaded stem 23 integral therewith to be screwed into the bracket portion 20. An integral nut section 24 is provided between the body portion and stem to facilitate turning of' the device. The body portion 22 is recessed, as indicated at 25, to rotatably receive and support a ball 28 which is retained in the socket by an inturned three of said balls, one upper and two lower or two upper and one lower, touch the wall of the vessel at any one time. The plunger is adapted torotate about its axis whereby its points of contact with the balls will change continuously and the balls in their retaining sockets can con- The area of the -wall I3 is proportioned so as to insure that the center of gravity of the article being weighed falls close to the central axis of the plunger thereby minimizing any friction at the points of contact oi the plunger with the balls. The area of the wall I3 is shown as less than one-sixth or the plunger area.

The guiding and centering devices are posie tioned within the air space of the plunger and are protected from oxidation, amalgamation or corrosion by the liquid and so that they can be readily and suitably lubricated. Furthermore, the arrangement of the guide devices within the plunger leaves the outside surface of the plunger Iii free and clear for the graduations so that the latter can be easily read; and in case the graduations are formed by grooves in the outer surface of the plunger, there is no danger of the guiding device becoming caught in such grooves in'such a way as to interfere with accurate movement of the plunger. Also the tubular stem I'! projecting from the tightly fitting cover into the outer vessel I in surrounding relation to the opening I5 in the cover prevents the spillage of liquid from the outer vessel in case the scale is tipped over.

Through calculation of plunger diameter for the specific liquid used, the article to be weighed gets its reading at the line of contact of the liquid With the wall of the plunger I0. This requires that only the plunger and the adjustment of its -guiding means need be accurate in order to insure accuracy in the weighing.

On the top surface of the cover member I5, a circular chart 21 in the form of a decalcomania transfer may be removably mounted (only half is shown). This chart contains various postage rates or any other desired indicia.

it will be understood that this improved weighing mechanism is not limited touse of the plunger and liquid in a confined vessel or container, such as the outer container I as shown, but may be used with the plunger immersed in larger bodies of liquid, i. e., the lweighing is not dependent upon the exact volume of liquid surrounding the plunger.

Changes in details might also be made without departing from the principle or scope of the invention.

Having thus described the invention, What I claim is:

1. A hydrostatic weighing scale comprising a cup-shaped outer vessel containing a supply of liquid, a cover member tightly tted upon the open end of the outer vessel, said cover having a central opening, a tubular stem depending from the cover member around said opening, a cupshaped plunger member inside said vessel having its bottom end submerged in said liquid, a tubular member supported centrally on the bottom wall of the plunger member and extending upwardly therefrom and through the tubular stem and opening in the cover member to a point above the cover member, a wall closing the upper end of said tubular member adapted to support an article to be weighed, there being a graduated scale carried by said plunger member adapted to coact with the level of the liquid for measuring the Weight of the supported article and spaced ball members supported by said tubular stem in a manner adapted to engage the inner surface of the plunger member for centering said plunger member in the outer vessel and for guiding its movements up and down in the liquid.

2.' A hydrostatic weighing scale comprising a cup-shaped outer vessel containing a supply of liquid, a cover member tightly tted upon the open end of the outer vessel, said cover member v having a central opening, a tubular stern depending from the cover member around said opening, a cup-shaped plunger member inside said vessel having its bottom end submerged in said liquid, a tubular member supported centrally on the bottom Wall of the plunger member and extending upwardly therefrom and through the tubular stem and opening in the cover member, a wall closing the upper end of said tubular member and adapted to support an article to be weighed, there being a graduated scale carried by said plunger member adapted to coact with the level of the liquid for measuring the weight of the supported article, and devices for centering and guiding the `plunger member including spaced brackets on the tubular stem adjacent its upper end and adjacent its lower end and ball members rotatably supported by said brackets and adapted to engage the inner surface of the plunger member.

3. A hydrostatic weighing scale comprising an outer vessel containing liquid and having a tight tting cover provided with a central opening, a cup-shaped plunger inside said vessel having its bottom end submerged in said liquid, a stem carried by said plunger in spaced relation to the side wall of the plunger and extending upwardly through said opening in the cover with its upper end formed to support an article to be weighed, there being a graduated scale on the plunger to coact with the level of said liquid for measuring the weight of the supported article, and means depending from said cover into the space between said stem and the side wall of said plunger and engaging the interior of the plunger wall for centering the plunger and guiding its movements.

4. A hydrostatic scale as dened in claim 3 wherein the last named means comprises a tubular portion, spaced brackets extending radially therefrom in spaced relation circumferentially thereof and balls rotatably supported by said brackets for frictionally engaging the inner surface of the plunger Wall.

5. A hydrostatic weighing scale comprising an outer vessel containing liquid and having a tight tting cover provided with a central opening, a cup-shaped plunger inside said vessel having its `bottom end submerged in said liquid, and having a coaxial stem in spaced relation to its side wall and extending upwardly through said opening in the cover with its upper end formed to support an article to be weighed, there being a graduated scale on the plunger to coact with the level of said liquid for measuring the Weight of the supported article, and centering and guiding means for said plunger carried by said cover and extending into the space between said stern and said side Wall of the plunger.

ALEXANDER F. JACKSON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 232,245 Deschamps Sept. 14, 1880 2,487,664 Morgan Nov. 8, 1948 FOREIGN PATENTS Number Country Date 3,171 Great Britain Aug. 7, 1879 of 1879 16,403 Great Britain July 23, 1902 

